Fix/cgroup2 bind mount shared cgroupns#5267
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Hi @kolyshkin would you like to move forward with this PR? |
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Forgot to submit pending review comments, my bad.
Overall it's almost ready.
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@lifubang @kolyshkin I have moved the checkpoint-related commit into a new PR: #5318, and fixed the other review suggestions. |
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| // Emulate cgroupns by bind-mounting the container cgroup path | ||
| // rather than the whole /sys/fs/cgroup. | ||
| bindM.Source = c.cgroup2Path | ||
| } else { |
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I'm not quite sure about this else wrt cgroup2Path -- do we only need to add MS_PRIVATE if there's no cgroupNS AND the cgroup2Path is not set?
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yes, you are right, MS_PRIVATE is mainly needed for the host cgroup namespace bind-mount case
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When cgroup namespaces is host, mounting a new cgroup2 fs instance for /sys/fs/cgroup can affect the host-visible cgroupfs mount state, including options such as nsdelegate. Avoid that by preferring a bind mount of the existing cgroup v2 hierarchy when cgroupns is host. Keep the existing cgroup2 mount-first logic for private cgroup namespaces, including the EPERM/EBUSY fallback to a bind mount and the rootless ENOENT masking behavior. Signed-off-by: sean <xujihui1985@gmail.com>
in host cgroupns, mount cgroupfs should not mutate the global superblock mount options, the test is to check when create container with host cgroupns, it should not mutate the global superblock options of host cgroupfs Signed-off-by: sean <xujihui1985@gmail.com>
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When cgroup namespaces is host, mounting a new cgroup2 fs instance for /sys/fs/cgroup can affect the host-visible cgroupfs mount state, including options such as nsdelegate.
Avoid that by preferring a bind mount of the existing cgroup v2 hierarchy when cgroupns is host. Keep the existing cgroup2 mount-first logic for private cgroup namespaces, including the EPERM/EBUSY fallback to a bind mount and the rootless ENOENT masking behavior.
this PR fix issue #5258